However, the Monmouth survey, which was conducted March 3–6, found Trump with a wider lead in the first two days of polling. The race tightened in the final two days, Monmouth said.

On Thursday and Friday, Trump had 39 percent support, followed by Cruz, at 22 percent, and Kasich, at 17 percent. On Saturday and Sunday, Trump was down to 32 percent, while Kasich came in at 26 percent and Cruz at 25 percent.

“After this past weekend’s mixed bag of results, Trump appears positioned for a win in Michigan, but the race may be tightening in the final hours,” said Monmouth pollster Patrick Murray. “Trump’s support may be dropping, while Kasich’s star could be rising.”

Kasich has been campaigning heavily in Michigan, which borders his home state of Ohio. He has picked up some high-profile endorsements in the state from Lt. Gov. Brian Calley, Rep. Mike Bishop and the editorial boards from some of the state’s largest newspapers.

On the Democratic side, Clinton takes 55 percent support over Sanders, at 42 percent.

Clinton is once again boosted by her support from minority voters. She leads Sanders, 68 to 27, among non-white voters, while the two are tied among white voters.

“Clinton had Michigan all to herself eight years ago after her opponents pulled out when the state violated party rules in scheduling its primary too early,” said Murray. “This time she appears to be holding on in the face of a tough challenge from Sanders.”

The Monmouth survey was conducted in full before the Democrats faced off at a debate in Flint, Mich., on Sunday night.

Michigan voters were split on which candidate would do a better job addressing the water crisis in that city, with 18 percent saying Clinton and 17 percent saying Sanders.

The Monmouth University survey of 402 likely Republican primary voters has a 4.9 percentage point margin of error.

The survey of 302 likely Democratic voters has a 5.6 percentage point margin of error.